This invention relates to a method for measuring sound absorption power of a theater (hall) chair with a human being seated thereon and a sound absorption dummy used for this method and, more particularly, to the method and dummy which can measure sound absorption capacity of a hall chair in such a state easily and accurately.
A sound absorption characteristic of a chair in a theater or auditorium (hereinafter referred to as "theater chair") is a very important factor in the acoustic designing of a theater. It has generally been customary in the past to measure a sound absorption characteristic of a hall chair per se in a state wherein a human being is not seated on the chair. The sound absorption characteristic of a hall chair should however be measured in a state wherein a human being is seated on the chair in question.
It has recently been proposed to provide a theater chair with a constant sound absorption power intended to enable an acoustic characteristic of a hall to remain unchanged between a state wherein a human being is seated on the hall chair and a state wherein he is not seated thereon (e.g., as described in the specification and drawings of Japanese Utility Model Application No. Hei 4-45924 filed by the assignee of the present invention). In designing such a hall chair, it is necessary to measure not only the sound absorption characteristics during an unseated state but also those during a seated state.
In a case where a sound absorption characteristic of a hall chair during a seated state is to be measured, a measurement is made under the condition that a human being is actually seated on the hall chair.
The method according to which the sound absorption characteristic is measured with a human being seated on the theater chair however has the following inconveniences:
1. Reliability and reproducability of a measured value are not adequate. Since the posture of the person seated on the hall chair differs from person to person and since presence of a human being affects temperature and humidity of the chamber (hall) in which the measurement is made, these factors cause measurement errors. Further, movement and posture of a human being and the clothing he wears during the measurement also affect the measurement very much.
2. It is difficult to compare results of the plural measurements with each other for the reasons described above in 1.
3. The measurement is an unpleasant experience for the human being seated on the hall chair and this causes the inconvenience described above in 1.
4. It is a troublesome task to collect ten to twenty persons to be measured at one time.
It is, therefore, an object of the invention to provide a method for measuring a sound absorption capacity capable of easily and accurately measuring a sound absorption capacity of a hall chair with a human being seated thereon and provide also a sound absorption dummy used for this method.